Field Engine modules
=======================
The Field Engine (FE) has limited number of instructions/operations to support most use cases.
There is a plan to add LuaJIT to be more flexible at the cost of performance.
The FE can allocate stream variables in a stream context, write a stream variable to a packet offset, change packet size, and so on.
*Examples of Field Engine uses:*
* Change ipv4.tos 1-10
* Change packet size to a random value in the range 64 to 9K
* Create a range of flows (change src_ip, dest_ip, src_port, dest_port)
* Update IPv4 checksum
The following snippet creates a range of 64 bytes packets ::
# split the range of IP to cores
#
class STLS1(object):
def __init__ (self):
self.fsize =64;
def create_stream (self):
# create a base packet and pad it to size
size = self.fsize - 4; # no FCS
base_pkt = Ether()/IP(src="16.0.0.1",dst="48.0.0.1")/UDP(dport=12,sport=1025)
pad = max(0, size - len(base_pkt)) * 'x'
vm = STLScVmRaw( [ STLVmFlowVar ( "ip_src",
min_value="10.0.0.1",
max_value="10.0.0.255",
size=4,
step=1,
op="inc"),
STLVmWrFlowVar (fv_name="ip_src",
pkt_offset= "IP.src" ), # write ip to packet IP.src
STLVmFixIpv4(offset = "IP") # fix checksum
],
split_by_field = "ip_src",
cache_size =255 # cache the packets, much better performance
);
pkt = STLPktBuilder(pkt = base_pkt/pad,
vm = vm)
stream = STLStream(packet = pkt,
mode = STLTXCont())
#print(stream.to_code())
return stream
def get_streams (self, direction = 0, **kwargs):
# create 1 stream
return [ self.create_stream() ]
The following snippet creates a SYN attack::
# create attack from random src_ip from 16.0.0.0-18.0.0.254 and random src_port 1025-65000
# attack 48.0.0.1 server
def create_stream (self):
# TCP SYN
base_pkt = Ether()/IP(dst="48.0.0.1")/TCP(dport=80,flags="S")
# vm
vm = STLScVmRaw( [ STLVmFlowVar(name="ip_src",
min_value="16.0.0.0",
max_value="18.0.0.254",
size=4, op="random"),
STLVmFlowVar(name="src_port",
min_value=1025,
max_value=65000,
size=2, op="random"),
STLVmWrFlowVar(fv_name="ip_src", pkt_offset= "IP.src" ),
STLVmFixIpv4(offset = "IP"), # fix checksum
STLVmWrFlowVar(fv_name="src_port",
pkt_offset= "TCP.sport") # fix udp len
]
)
pkt = STLPktBuilder(pkt = base_pkt,
vm = vm)
return STLStream(packet = pkt,
random_seed = 0x1234,# can be remove. will give the same random value any run
mode = STLTXCont())
STLScVmRaw class
----------------
Aggregate raw instructions objects
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLScVmRaw
:members:
:member-order: bysource
STLVmFlowVar
------------
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLVmFlowVar
:members:
:member-order: bysource
STLVmWrMaskFlowVar
------------------
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLVmWrMaskFlowVar
:members:
:member-order: bysource
STLVmFixChecksumHw
--------------------
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLVmFixChecksumHw
:members:
:member-order: bysource
STLVmFixIpv4
------------------
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLVmFixIpv4
:members:
:member-order: bysource
STLVmTrimPktSize
------------------
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLVmTrimPktSize
:members:
:member-order: bysource
STLVmTupleGen
------------------
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLVmTupleGen
:members:
:member-order: bysource
STLVmFlowVarRepetableRandom
----------------------------
.. autoclass:: trex_stl_lib.trex_stl_packet_builder_scapy.STLVmFlowVarRepetableRandom
:members:
:member-order: bysource
Field Engine snippet
--------------------
.. code-block:: python
# FE Example1
base_pkt = Ether()/IP(src="16.0.0.1",dst="48.0.0.1")/UDP(dport=12,sport=1025)
pad = max(0, size - len(base_pkt)) * 'x'
vm = STLScVmRaw( [ STLVmTupleGen ( ip_min="16.0.0.1", ip_max="16.0.0.2",
port_min=1025, port_max=65535,
name="tuple"), # define tuple gen
# write ip to packet IP.src
STLVmWrFlowVar (fv_name="tuple.ip", pkt_offset= "IP.src" ),
STLVmFixIpv4(offset = "IP"), # fix checksum
STLVmWrFlowVar (fv_name="tuple.port", pkt_offset= "UDP.sport" ) #write udp.port
]
);
pkt = STLPktBuilder(pkt = base_pkt/pad,
vm = vm)
.. code-block:: python
# FE Example2
#range of source mac-addr
base_pkt = Ether()/IP(src="16.0.0.1",dst="48.0.0.1")/UDP(dport=12,sport=1025)
pad = max(0, size - len(base_pkt)) * 'x'
vm = STLScVmRaw( [ STLVmFlowVar(name="mac_src",
min_value=1,
max_value=30,
size=2, op="dec",step=1),
STLVmWrMaskFlowVar(fv_name="mac_src",
pkt_offset= 11,
pkt_cast_size=1,
mask=0xff)
]
)
.. code-block:: python
# FE Example3
#IP dest would have 10 random values betwean 48.0.0.1 48.0.0.255
base_pkt = Ether()/IP(src=src_ip,dst=dst_ip)/UDP(dport=12,sport=1025)
pad = max(0, size - len(base_pkt)) * 'x'
vm = STLScVmRaw( [ STLVmFlowVar ( "ip_src", min_value="10.0.0.1",
max_value="10.0.0.255", size=4, step=1,op="inc"),
STLVmFlowVarRepetableRandom ( "ip_dst",
min_value="48.0.0.1",
max_value="48.0.0.255",
size=4,
limit=10, seed=0x1235),
STLVmWrFlowVar (fv_name="ip_src", pkt_offset= "IP.src" ), # write ip to packet IP.src
STLVmWrFlowVar (fv_name="ip_dst", pkt_offset= "IP.dst" ), # write ip to packet IP.dst
STLVmFixIpv4(offset = "IP") # fix checksum
]
,split_by_field = "ip_src" # split to cores base on the tuple generator
,cache_size = cache_size # the cache size
);